This application claims the priority of Austrian Patent Application Serial No. A 635/98, filed Apr. 14, 1998, the subject matter of which is incorporated herein by reference.
The present invention relates to a drive system for two counter-rotating cylindrical brushes of a floor cleaning machine which includes a motor, a gear mechanism and a force transmitting system for transmitting a torque from the gear mechanism to the cylindrical brushes.
Floor cleaning machines with two counter-rotating cylindrical brushes are known. Such machines typically include a rotating drum that is arranged between the cylindrical brushes and has a rotation axis that is located above the rotation axes of the cylindrical brushes. Water is applied to the floor to be cleaned or to one of the brushes, and the water together with the dirt, picked up by the brushes, is then propelled towards the drum surface. A water film forms on the drum which holds the dirt that is picked up from the floor on the surface of the drum. Also provided are devices for lifting the soiled water film from the drum and transferring the soiled water film to a waste water container.
In general, it is an object of the invention to provide an improved design of such floor cleaning machines. The object is attained by several design features described hereinafter.
A first important aspect of the invention is the drive system. The drive system includesxe2x80x94as mentioned abovexe2x80x94a motor, a gear mechanism and a force transmitting system for transmitting a torque from the gear mechanism to the cylindrical brushes. Conventional gear mechanisms have a single driven shaft. Typically, the two cylindrical brushes are driven by a multistage gear drive disposed on each cylindrical brush, i.e., by several meshing gear wheels having parallel rotation axes. A gear mechanism constructed in this manner disadvantageously requires multiple stages to drive the brushes, which significantly reduces the efficiency of the drive system and also generates objectionable noise.
It is therefore an object of the invention to obviate these drawbacks, and to provide a drive system of the type described above with a high efficiency.
This object is attained in accordance with the invention by providing each cylindrical brush with its own separate driven shaft.
In this way, both cylindrical brushes can be connected directly and independently of each other to the gear mechanism, and a malfunction of one drive connection does not affect the other drive connection. The direct connection of each brush to the gear mechanism produces the required high efficiency.
According to a preferred embodiment of the invention, the force transmitting system may include toothed disks and toothed belts which are secured to the driven shafts and to the shafts of the cylindrical brushes and which connect one of the toothed disks of the driven shaft with a respective toothed disk located on the cylindrical brush. A toothed belt drive of this type is very effective and highly efficient. The toothed belt drive also operates very quietly, so that of the cleaning machine produces very little noise.
According to another embodiment of the invention, a further toothed disk may be secured on a driven shaft and connected via another toothed belt to a toothed disk that is secured on the driven shaft of the drum. The drum is then driven independently from the brushes, so that the drum is still operational in the event that the drives of the brushes malfunction. Furthermore, the toothed belt drive is very effective and operates very quietly.
According to another feature of the drive system of the invention, the gear mechanism may include a pinion secured to the motor drive shaft and two primary gear wheels that engage with the pinion, as well as a secondary gear wheels meshing with the primary gear wheels, wherein the first driven shaft is connected to one of the primary gear wheels and the second driven shaft is connected to the secondary gear wheel. In this manner, the counter-rotation of the cylindrical brushes can be attained employing only a few components. The driven shafts of the gear mechanism are connected to the motor pinion only via one or two stages, thereby further contributing to the high overall efficiency of the drive system.
According to yet another feature of the invention, the pinion, the primary gear wheels and the secondary gear wheel may be implemented as spur gears made of steel. This guarantees a long lifetime of the gear wheels.
According to another advantageous feature of the invention, the pinion, the primary gear wheels and the secondary gear wheel may be helical gears that are known to produce a particularly low noise level .
The toothed disks of the force transmitting system may also be made of steel, aluminum, plastic and the like. Toothed disks made of steel advantageously have a long lifetime which reduces the frequency of repairs of the cleaning machine. Plastic and aluminum gears advantageously produce low noise levels.
According to another embodiment of the invention, the motor is a synchronous motor. Motors of this type can be controlled with relatively simple control circuits. Moreover, synchronous motors are known to support the high brush rotation speed required, for example, for waxing floors. Consequently, the cleaning machine according to the invention is suitable for waxing floors, in particular marble floors.
Advantageously, an electronic device for controlling the rotation speed of the motor can be provided to adapt the cleaning machine to different dirt conditions encountered in practice. The motor can be started smoothly with such control, thereby improving the motor lifetime.
According to another advantageous feature, the floor cleaning machine of the invention includes a stripping device for lifting the soiled water film from the floor, transferring the film to the drum and then transferring the soiled water film to a waste water container. Such floor cleaning machines with a stripping device with at least one rotating brush, preferably a cylindrical brush, and with a drum, on which a water film is disposed and to which the dirt picked up by the brush is transferred, are known in the art. The stripping device lifts this soiled water film from the drum and transfers the film to a waste water container. The stripping device is formed as a strip which contacts the outer surface of the drum along the entire width of the drum.
Conventionally, the strip is biased by a plurality of spaced-apart springs and thereby pressed against the surface of the drum. The thus realized pressing of the strip at only spaced-apart localized points may cause problems, since the water film is then properly lifted from the drum surface only in certain sections, while the water film in other sections forms a dam in front of the strip before being lifted. This significantly impairs the reliable removal of dirt.
It is therefore another object of invention to provide an improved stripping device which obviates these drawbacks and ensures that the water film is reliably lifted across the entire width of the drum.
Thus, according to another aspect of the invention, a rigid strip holder is provided that extends substantially across the entire lengths of the strip, wherein the strip holder is biased towards the surface of the drum by at least one spring. The rigid strip holder distributes the spring bias force evenly across the entire length of the strip and therefore biases the strip against the drum surface with a biasing force that is constant over the entire length of the strip. Uneven biasing forces that can otherwise cause the water film to form a dam, are thereby eliminated.
Advantageously, the strip holder is pivotally supported, with the spring pivoting the portion of the strip holder carrying the strip towards the drum surface. This type of support can be easily implemented.
According to yet another feature of the invention, the strip holder can be secured in fixed rotative engagement on a pivot shaft which projects beyond the end faces of the strip holder and is supported in the side members of the floor cleaning machine. A lever is arranged on at least one pivot shaft end that projects beyond the side member, with the at least one spring acting on the lever. The spring acting on the lever can then be secured to the side member, so that the floor cleaning machine is of significantly simpler construction than could otherwise be achieved if the spring were attached at a level with the drum.
According to another feature of the invention, the spring may be implemented as a compression spring, with one end of the spring supported on the side member and the other end of the spring supported on the lever. Such springs are standard components, and their use reduces the manufacturing cost and facilitates maintenance of the floor cleaning machine according to the invention.
According to yet another embodiment of the invention, the compression spring may be accommodated in a housing formed as a hollow cylinder and closed off on one end, wherein the housing is supported for rotation parallel to the plane of the side member, with the one end of the compression spring being supported on the bottom of the housing, whereas the second end is supported on a piston extending into the housing and rotatably supported on the lever. The compression spring is thereby encapsulated and sealed against dust and protected from the environment.
According to another embodiment of the invention, the spring can be formed as a tension spring, with one end of the spring secured to a side member and the other end of the spring secured to the lever. These springs are also standard components, so that their use results in a simplified maintenance of the floor cleaning machine and in reduced the manufacturing cost.
In addition, a conventional stripping device adapted for use with a floor cleaning machine of a type having at least one rotating brush, preferably a cylindrical brush, and a rotating drum on which a water film is arranged for receiving dirt picked up by the brush, and provided for lifting the soiled water film from the drum and transferring the film to a waste water container, has the following further drawback: Dirt, in particular dirt in form of long fibers, tends to accumulate and form a dam on the strip, and is therefore not immediately transferred to the waste water container. When the dam is formed on the stripping device, the stripping device frequently clogs, interrupting the cleaning process.
It is therefore an object of the invention, to provide a new design of a stripping device, which ensures that the dirt is transferred directly to the waste water container.
According to the invention, this object is attained by providing a rotating cylindrical brush that extends substantially across the entire width of the drum, with the free brush ends of the brush bearing upon the drum surface.
Unlike conventional stripping devices, the stripping device according to the present invention lifts the dirt from the drum surface and simultaneously transfers the dirt to the waste container. Consequently, the dirt cannot form a dam.
Another aspect of the present invention relates to the handle of the floor cleaning machine for manual maneuvering the machine. Conventional floor cleaning machines that include a motor, preferably an electric motor, for driving cleaning devices, such as cylindrical brushes, and at least one switch to switch the motor on and off, employ a handle which operates the switch with a portion of the handle. Typically, the switch is actuated by pivoting the entire handle. For example, if the handle is oriented perpendicular to the floor, the switch is switched OFF, whereas when the handle is pivoted by a predetermined angle, then the switch is moved into an ON position, which starts the floor cleaning machine. This mode of actuation has however the drawback that the machine can be inadvertently switched on even though the intention of the user is only to move the machine with the handle.
It is therefore another object of the invention to provide an improved handle which can be tilted in an arbitrary direction without activating the switch.
This object is attained according to the present invention by providing a switch that is arranged at a fixed location on the handle, wherein the portion of the handle that actuates the switch is implemented in form of a lever that can be pivoted with respect to the handle. In this way, the switch can be actuated independent of the rotation angle of the handle, thereby entirely eliminating the disadvantages described above.
Advantageously, the lever may include a pivot shaft supported in the handle, wherein a separate actuator is provided on the pivot shaft for each switch, and wherein the actuating element of the switch is attached to the handle and located in the path along which the actuator is rotated. The switch can then be arranged inside the handle and effectively protected from the environment.
According to another embodiment of the present invention, the actuator can be formed by a cylindrical disk that is eccentrically secured to the rotating shaft. This configuration realizes a smooth activation of the actuating element, thereby extending the lifetime of the switch.
According to another feature of the invention, the at least one switch can be a microswitch having a lever as an actuating element. Microswitches are standard components which contribute to reduced manufacturing costs of the floor cleaning machine. Moreover, microswitches have a long lifetime and therefore make the floor cleaning machine more reliable.
The present invention also relates to a handle for a floor cleaning machine with cleaning devices that make contact with the floor, in particular cylindrical brushes, as well as with an undercarriage having wheels supported in wheel supports which are movable with respect to the cleaning devices. The wheels can thereby be raised above or lowered below the section of the cleaning devices that contacts the floor, by using a portion of the handle. Conventionally, the wheel supports are normally raised and lowered by moving the entire handle. For example, the wheel supports are lowered by orienting the handle perpendicular to the floor, whereas the wheel supports are raised by rotating the handle by a certain angle. In this way, however, the undercarriage can be inadvertently raised when the machine is only to be moved using the handle.
It is therefore an object of the present invention to provide an improved handle which can be tilted regardless if the wheel supports are to be raised or lowered.
This object is attained in accordance with the invention, by providing the portion of the handle, which raises the undercarriage, in the form of a lever which is pivotally supported on the handle, and by providing cables having first ends secured to the wheel support of the undercarriage and second ends secured to the lever. The wheel supports can then be lifted independently of the tilt angle of the handle, thereby eliminating the disadvantages described above.
According to another feature of the present invention, the lever may include a pivot shaft supported on the handle, wherein the second end of the cables is secured to the outer surface of the pivot shaft. In this way, the cables can be routed inside the handle and thereby effectively protected from the environment. Advantageously, the cables can be guided in a particularly good manner by attaching disks on the pivot shaft on both sides of the attachment points of the cables.
The invention also relates to a floor cleaning machine of a type including at least one rotating brush, preferably a cylindrical brush, a rotating drum having a water film that receives the dirt picked up by the brush, and a nozzle for applying water for the water film to the floor to be cleaned or at least to a rotating brush. Common to all conventional floor cleaning machines is the fact that water for the water film is ejected through nozzles that are rigidly attached to the machine and are oriented in such a way that the cone of the water jet either impinges entirely on the floor to be cleaned or entirely on a brush.
Water, however, is preferably applied to different areas depending on the type of the floor to be cleaned: In floors that strongly absorb water, for example carpets, water should be applied to the brush and not to the absorbent floor; whereas in floors that do not absorb water, for example tiled floors, concrete or parquet, water should be aimed directly to the floor. Conventional machines with rigid attachment of the nozzles to the floor cleaning machine can only be used for a specific type of floor.
It is therefore an object of the invention, to provide an improved floor cleaning machine, which can be equally employed with absorbent and non-absorbent floors.
This object is attained in accordance with the present invention, by so securing the nozzle to the floor cleaning machine as to be rotatable about an axis that is approximately perpendicular to the symmetry axis of the water spray cone. The user can then easily adjust the location where the jet spray cone impinges on the floor and/or brush and select the orientation of the cone according to the requirements of the floor to be cleaned.
Advantageously, the nozzle may have at least one locking lug which cooperates with recesses disposed in the region of the nozzle of the floor cleaning machine. In this way, the nozzle cannot be tilted by the hydraulic force and the recoil forces acting on the nozzle, and therefore remains in the position selected by the user.
The present invention also relates to a transport cart for a floor cleaning machine of a type described above, with wheels and a hand grip. Transport carts that are specifically designed for floor cleaning machines are not known in the art. Until now, floor cleaning machines could only be moved with the help of the undercarriage attached to the machinesxe2x80x94if such undercarriage is provided at all. As the undercarriage of the floor cleaning machines typically has relatively small wheels, a maneuvering becomes difficult when negotiating obstacles, such as doors saddles or low steps. Alternatively, the use of common transport carts having a frame, four wheels, a support surface and a hand grip was proposed. While these common transport carts do not encounter the problems as discussed above, because they significantly greater wheels, these carts, however, make it difficult to move the floor cleaning machine since the machine has to be lifted by hand onto and from the support surface, which is time-consuming and exhausting.
It is therefore an object of the invention, to provide an improved transport cart which is simple in design and can receive a floor cleaning machine such that the floor cleaning machine can be moved onto and from the transport cart in a simple and ergonomically advantageous manner.
This object is attained in accordance with the present invention, by providing a transport cart which includes a frame having a handle, a mounting, connected to a handle-distal end of the frame, for support of wheels for mobility of the frame, support braces, secured to the mounting, for supporting the transport cart; and, receiving rods, secured to the mounting, for engagement in pockets of the floor cleaning machine. Because of its simple construction, the transport cart can be easily and inexpensively manufactured. In addition, the transport cart is small and therefore takes up very little space. Since the receiving rods can engage pockets provided in the floor cleaning machine, there is no need to lift the floor cleaning machine by hand for placement onto the transport cart or removal from the transport cart.
According to another feature of the present invention, the hand grip may include holders for spare parts for the floor cleaning machine, in particular replacement brushes. In this way, essential replacement parts can be stored at specific locations known to the user of the floor cleaning machine and are readily accessible.
In addition, at least one coupling member may be provided, such as a rope, a rigid bracket and the like, which can be attached at one end to the frame and at the other hand to the floor cleaning machine, after the machine is placed onto the transport cart, for reliably securing the floor cleaning machine to the transport cart.